It is known in the art relating to air outlet structures for automotive vehicles to provide a butterfly valve or door upstream from an airflow directionality control device to control the volume of air through the control device. The valve may be a conventional circular, oval or rectangular plate member. The valve may be mounted on a shaft to rotate the valve within the air outlet between open and closed positions.
The configuration of the valve is such that when the valve is in the closed position, it seals against the walls of the air outlet, blocking the airflow therein. A problem with this configuration is that the valve inherently consumes more packaging volume in the fore and aft direction, or open position, due to the design. The air outlet duct must be longer than is necessary to accommodate the diameter or width of the valve. Therefore, it is desirable to provide a shutoff valve or door that requires less space within the air outlet distribution system.